I had 2 that would escape the run every day. I felt like they must have been laying. I tried following the one, and lookng everywhere. Finally, one day, I sat outside for almost an hour following her around before she snuck into a small run down, falling apart shed in my neighbors yard. Behind the pile of junk in there,in the back corner, was a pile of 13 eggs.
I marked her( to be able to tell her from the rest), and kept her locked up for a few days till she laid in the nestbox.
Now the other one- I don't know. There was an egg in the nestbox once, and for a month later there wasn't one. I have looked all over my yard, and my neighbors yards, and cannot find a pile of eggs. So it is possible she wasn't laying any. Or it's possible they are trickier than I give them credit for.